For the country's estimated 35 million contact lens users, cleansing and replacing their lenses becomes a routine that is just as normal -- and seemingly safe -- as brushing their hair or flossing their teeth.
Just ask Paige Reichardt, of Valparaiso, Ind.., an ABCNews.com reader who says she wore her contacts for 48 years without any significant eye problems.
That changed in November 2005, when she contracted an aggressive parasitic infection in one of her eyes called Acanthamoeba keratitis, a disease for which 85 percent of victims are contact lens wearers.
Reichardt shared her chilling story on the ABCNews.com discussion boards.
"I was told on the first day that I was diagnosed that they would try to save my eye," she said. "So I knew from the start that it was serious."
The treatment, like the disease, was serious. While doctors fought for her eye, she says, she endured a number of unpleasant therapies. One of her medications was a diluted version of the same chemical used in swimming pool cleaners. "You can imagine how that feels," she said.
When the treatments failed, Reichardt endured four corneal transplant surgeries in five weeks as the disease spread and continued to destroy her eye, bit by bit.
"It's a diabolical disease," she said. "I felt like I was in a science fiction movie because there was no way to kill these damn things." In the end, Reichardt lost her eye to the disease.
Her case was one of 138 across the country that sparked a voluntary recall of the popular Advanced Medical Optics Complete MoisturePlus Multi-Purpose Solution for contacts last week.
The company insists there is no evidence that its product is contaminated with Acanthamoeba, which is normally found in soil and fresh water but rarely targets humans. The Centers for Disease Control and Prevention has urged consumers, however, to throw away any bottles they still have.
It's not the first time that contact lens solution has come under scrutiny; last year, investigators implicated Bausch & Lomb's ReNu MoistureLoc solution in a rash of fungal eye infections that affected 164 contact wearers.
Doctors say that amoebic and fungal infections are only two of the rare but numerous complications that come part and parcel with the use of contact lenses, risks of which many users themselves may not be aware.
"I want people to do the research to see why this happens," Reichardt said. "It is kind of frustrating for those of us victims when they say that this is rare, like it's never going to happen to you."
Are Users Aware of the Dangers?
"There's nothing that is without some degree of risk, and contact lenses are no exception," said Dr. John Sutphin, professor and chairman of ophthalmology at the University of Kansas Medical School.
Since contact lens use is so prevalent, the real question is whether the millions of those who use them daily are aware of the possible health risks, however rare.
Mild problems include conjunctivitis, an inflammation commonly known as "pink eye" that can be caused by a bacterial infection. Generally, a few days of eye drops and care can completely resolve this problem.
On the other side of the spectrum are Acanthamoeba, pseudomonas and E. coli infections that have the potential to rob victims of their sight or even their entire eye.
There are long-term risks as well. Sutphin says longtime contact lens users can suffer from a condition called stem cell deficiency, in which years of contact use can change the eye's ability to heal itself. There is also a small, but possible, risk of thinning of the cornea, the clear, windowlike portion of the front of the eye.
But what are the actual risks? Sutphin says the chances of most serious eye problems related to contact lens use are between two and four cases in 10,000 users, at most.
And the incidence of Acanthamoeba keratitis in the United States has been estimated by the CDC at approximately one to two cases per million contact lens users.
"By most standards this is not a lot of people," said Dr. Randy Epstein, professor of ophthalmology at Rush University Medical Center and one of the doctors who treated Reichardt.
"But if you look at cases like [Reichardt's] and see how devastating it can be, even a few cases become very significant."
Because of these risks, some are calling for more prominent labeling on contact lens packaging and solution bottles.
"They need to have a huge warning label put on the packaging of contact lenses and solution that says not to use tap water to clean the lenses and not to swim with the contacts in your eyes," Epstein said.
"If everyone took the time to read the warning labels and understand the proper care procedures for contacts, it probably wouldn't be as much of a concern. The problem is, most people don't take the time to read them. This is a huge potential public health problem," Epstein said.
Reichardt agrees that many users may not be aware of safety guidelines and warnings. "They say, 'Follow the manufacturer's instructions,'" she said. "What instructions are we supposed to be following? "They need to take responsibility for putting warnings on the outside of the box."
Complicating the issue, Epstein says, are services like 1-800 Contacts, which offer contact lenses without an eye doctor's consultation or necessary follow-up.
"It used to be that we were providing a service when it came to contact lenses," he said. "Now they're just a commodity."
Watch Out for Your Eyes
Fortunately, there are steps that contact wearers can take to safeguard their eyes:
Contacts and water don't mix. Removing your contacts before swimming or showering is arguably the best way to protect against potentially sight-robbing infections.
If possible, go disposable. It may cost a bit more, but Sutphin says this strategy limits the danger of bacterial or fungal infection.
Only use the contact lens solution appropriate to your lenses to cleanse them. Homemade solutions using tap water are much more likely to lead to infection.
If you use reusable lenses, store them in the proper case. Rinse the case after every use, and replace it at least once every three months.
Try to avoid wearing your lenses overnight. Wearing a lens overnight leads to a tenfold higher risk of infection than regular daily use, Sutphin says.
If your eyes are irritated or red, it's time to break out the glasses. "The biggest mistake you can make is if your eye is irritated and you wear your contacts anyway," Epstein said.
If you develop any symptoms such as eye pain, eye redness, blurred vision, sensitivity to light, sensation of something in the eye or excessive tearing, contact your ophthalmic doctor early. "Problems that are caught early are very treatable," Sutphin said. "Caught later, they can sometimes get out of hand."